Rotary valve mounting assembly

ABSTRACT

An improved mounting assembly supports a rotary stream-switching valve of the type having a housing and a rotor. The rotor includes a shaft and a sealing member having stream diverting grooves. The mounting assembly supports the entire valve from the valve shaft through a bushing slidably engaging over the shaft. One end of the bushing is attached to a bracket which can be secured to a suitable base. Engagement between projections on the housing and elements of the bracket prevents the housing from rotating when the valve shaft is turned to accomplish the desired stream switching. However, when sideways thrusts are imparted to the valve shaft, the valve housing is free to cock or shift with respect to the mounting so that there is no relative movement between the shaft and the housing as would tend to deform or damage the sealing member.

United States Patent 1 [72] inventor Richard N. King, Jr. Natick, Mass.

2! Appl. No. 761,983

[22] Filed [45} Patented [73] Assignee [54] ROTARY VALVE MOUNTINGASSEMBLY 13 Claims, 4 Drawing Figs.

52 u.s.c| 137/343,

248/67; 137/360 51 mm runs/00 so FieldofSearch 137/343,

' 360', 251/324(in part), 325(in part); 248/67, 56

3,122,168 2/1964 Wright 25l/367X 3,199,538 8/1965 Anthon 251/367X3,331,386 7/1967 Politz 137/36OX 3,366,356 1/1968 Fisher 248/56 PrimaryExaminer-Samuel Scott Attorney-Cesari & McKenna ABSTRACT: An improvedmounting assembly supports a rotary stream-switching valve of the typehaving a housing and a rotor. The rotor includes a shaft and a sealingmember having stream diverting grooves. The mounting assembly supportsthe entire valve from the valve shaft through a bushing slidablyengaging over the shaft. One end of the bushing is attached to. abracket which can be secured to a suitable base. Engagement betweenprojections on the housing and elements of the bracket prevents thehousing from rotating when the valve shaft is turned to accomplish thedesired stream switching. However, when sideways thrusts are imparted tothe valve shaft, the valve housing is free to cock or shift with respectto the mounting so that there is no relative movement between the shaftand the housing as would tend to defonn or damage the sealing member.

" PATEN T ED JAN 19 I97! FIG.

F G HNVENTOR RICHARD N. KING,JR.

ATTORNE S ROTARY VALVE MOUNTING ASSEMBLY BACKGROUND OF THE INVENTIONThis invention relates to a rotary valve assembly. It relates moreparticularly to an improved mounting for a rotary stream-switching valvefor use in the transport lines of liquid chromatography and samplingsystems.

Valves of this type usually comprise a generally cylindrical housing.Small tubes communicate with radial ports extending to a central axialpassage in the housing which contains a rotor. The rotor includes aprotruding valve shaft and a sealing I member which resiliently engagesthe wall of the housing passage. The surface of the sealing member hasstream-diverting grooves in contact with the wall of the passage. Byrotating the valve rotor to selected angular positions relative to thehousing, the grooves in the sealing member may be positioned to connectselected ones of the ports in the valve housing. Typical rotary valvesof this type are described in US. Pats. 2,757,541; 3,034,528 and3,329,166.

It is essential that the valves used in. the transport lines of liquidchromatography systems be free of leakage. In addition, the valvecomponents must be constructed of materials which are extremelyresistant to strong organic solvents. Thus, in the best valves, thevalve housing and rotor are constructed of stainless steel, while thesealing member is made of polytetraflouroethylene or. other similarinert, relatively resilient plastic. Each valve is designed tospring-load the plastic sealing member to provide sufficient sealing orcontact pressure between the sealing member and the housing to preventleakage.

In actual practice, however, prior rotary valves of this type do beginto leakafter a-relatively short period of use. The leakageis dueprimarily to deformation of the sealing member because of inadvertentsideways thrust on the valve shaft by the operator. That is, an operatormayaccidentally turn the rotor into its stops, thereby imparting asideways thrust to it; or. he may pull down on it. While these sidewaysforces may be relatively small, they are often enough to producesufficient cold flow of the plastic in the sealing member to permanentlydeform it and cause leakage In many cases, even slight leakage is enoughto spoil the chromatographic analysis; at the very least, it results inthe system having to be shut down while the valve is repaired orreplaced.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a mounting assembly for a rotary valve whichprolongs the useful life of the valve itself.

Another object of the invention is to provide a mounting assembly for arotaryvalve which minimizes stresses on the valve components which tendto cause the valve to leak.

Still another object of the invention is to provide an improved rotaryvalve-mounting assembly which is relatively inexpensive to manufactureand easy to install.

Another object of the invention is to provide a standard rotary valvemounting assembly which is suitable for use with different rotary valvemodels.

Still another object of the invention is to provide an improved mountingassembly for a rotary valve which minimizes unwanted relative movementbetween the stationary and moving components of the valve.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the features of construction,combination of elements, and arrangement of parts which will beexemplified in the construction hereinafter set forth, and the scope ofthe invention will be indicated in the claims.

Briefly, the present mounting assembly supports the entire valve by thevalve rotor, or more specifically by the rotor extension or shaft. Itincludes a bushing which slidably engages over the shaft. The end of thebushing facing the housing is LII rigidly secured to a bracket which, inuse, is affixed to a supporting wall.

Screws projecting from the housing engage portions of the bracket toprevent the housing from rotating relative to the bracket and also toprevent the valve from pulling away from the mounting assembly. Thus,when an operator turns the valve shaft, the rotor turns inside thehousing because the latter cannot rotate because of the aforesaidengagement with the bracket and so the desired stream switching takesplace. However, if the operator inadvertently turns the valve shaft intothe stops or otherwise pushes sideways on it, the valve housing is freeto cock or tilt relative to the mounting assembly. Consequently, thereis no relative movement between the rotor and the housing as would tendto compress or deform the plastic-sealing member on the rotor, and causeleakage.

In some applications, a collar is affixed to the valve shaft just aheadof the bushing. This limits movement of the rotor towards the housingand minimizes damage to the valve-sealing member due to axial thrusts onthe valve shaft.

Valves supported by my improved mounting assembly suffer a minimumamount of down time and have a relatively long, useful life. Moreover,when the: sealing member in the valve finally does require replacement,the valve can be removed easily from its mounting and replaced withoutrequiring any special tools or other equipment. Also, the presentmounting has only a few parts all of which are relatively easy andinexpensive to make.

BRIEF DESCRIPTION OF THE DRAWING For a fuller understanding of thenature and objects of the invention, reference should be had to thefollowing detailed description taken in connection with the accompanyingdrawing, in which:

FIG. I is an exploded perspective view showing the elements of my,mounting assembly and a typical rotary valve;

FIG. 2 is a side elevational view with parts broken away of the FIG. 1elements fully assembled on; the valve;-

FIG. 3 is a top plan view thereof; and

FIG. 4 is a front elevational view of the mounting assembly supporting adifferent valve model.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 2 of thedrawing, the present mounting assembly indicated generally at 10 issecured to a supporting housing wall 12. The mounting assembly rigidlysupports a conventional rotary stream-switching valve indicatedgenerally at 14.

Valve 14 has a generally cylindrical housing 16 with a central axialpassage 18. A rotor assembly 20 is mounted in passage 18 and carries asleevelike plastic-sealing member (not shown) which tightly engages thepassage 18 wall. Rotor assembly 20 also has a relatively long shaft 22protruding from housing 16 which extends through mounting assembly 10and a passage 23 in wall 12. A knob or handle 24 secured to the free endof valve shaft 22 facilitates turning rotor assembly 20 with respect toits housing 16.

Referring now to FIG. 1, when rotor assembly 20 is turned by its handle24, its sealing member interconnects selected ones of tubes 26 whichcommunicate with passage 18. The illustrated valve has only twooperative positions. In one position, valve shaft 22 is turned fullyclockwise until a lug 28 projecting up from the shaft engages a pin 30projecting out from the front face 16a of housing 16. In the otheroperative position of the valve, the valve shaft is turned fullycounterclockwise until lug 28 engages a pin 32 extending out fromhousing 16. It should be understood, however, that streamswitchingvalves used in chromatography and sampling systems may have severaloperative positions of the rotor and as many as twenty or more suchtubes 26 to accomplish very complex stream switching. The constructionand operation of these valves are described in detail in theaforementioned US. patents.

Still referring to FIG. 2, mounting assembly comprises three basicelements, to wit: a bracket 34, a bushing 36 and a nut 38. All of theseelements coact to support valve 10 from its stem 22 so that sidewaysthrusts on the valve will not damage the rotor assembly 20, andspecifically its internal plastic-sealing member. Yet, assembly 10permits the operator to turn valve shaft 22 to accomplish the desiredstream switching.

Bracket 34 comprises a generally T-shaped plate 40 having arms 40a and40b and a leg 42. A passage 44 is formed in plate 40 above leg 42 andmidway between arms 40a and 40b. The diameter of opening 44 is largerthan that of shaft 22 so that the latter can be loosely received inopening 44.

Leg 42 is folded back on itself to form an upstanding lip 42a. Lip 42::extends up to a line approximately even with the lower edge of opening44. For reasons to be described in more detail later, a V-shaped groove46 is formed in lip 42a midway between the side edges thereof. Also, thebottom of groove 46 is rounded out at 48.

A pair of screw openings 50 are formed in arms 40a and 40b on each sideof opening 44. In use, screws 52 are inserted through openings 50 tosecure bracket 40 to its supporting wall 12 as shown in FIG. 3.

Still referring to FIG. 1, bushing 36 is a generally cylindrical sleevehaving an inner diameter only slightly larger than the diameter of shaft22. The outer diameter of bushing 36 is slightly larger than that ofopening 44 in bracket 40. Bushing 36 also has a reduced diameterthreaded portion 52 at one end thereof. The diameter of threaded portion52 is slightly less than that of opening 44 so that end 52 can bereceived snugly in opening 44. The opposite end 360 of bushing 36 isbeveled. Also, opposite side portions 54 of the bushing are flattened tofacilitate engaging the bushing by a wrench or other similar toolcapable of rotating it about its longitudinal axis.

Nut 38 is a conventional square nut having a centrally threaded opening58 arranged to threadedly engage end portion 52 of bushing 36.

Prior to installing valve 14 in mounting assembly 10, a pair of similar,flatheaded screws 60a and 60b are screwed into valve housing face 16a onopposite sides of valve shaft 22. Screws 60a and 60b have relativelylong shanks 62a and 62b, respectively, terminating in relatively largediameter slotted heads 64a and 64b, respectively.

When mounting valve 14, nut 38 is first slid onto shaft 22. Then, thevalve shaft is inserted through opening 40 in bracket 34 so that lip 42aon the bracket faces housing face 16a as seen in FIG. 1. Next bracket 34is cocked slightly to permit lip 42a to engage under screws 60a and 60b.The length of the screw shanks 62a and 62b is such that when bracket 34is oriented vertically, i.e. perpendicular to the axis of valve stem 22,the top edge of lip 42a engages behind the screw heads 64a and 64b asbest seen in FIGS. 2 and 3.

Following this, bushing 36 is slid onto valve shaft 22 until itsthreaded end portion 52 protrudes through opening 40 in bracket 34. Nut38 is then screwed down end portion 52. The bushing and nut aretightened by turning the bushing with a wrench engaging its flattenedportions 54. Nut 38 is prevented from turning along with the bushingbecause it engages one or both of screw heads 64a and 64b.

Following this, shaft 22 and bushing 36 are inserted through passage 23in wall 12 and bracket 34 is secured to wall 12 by screws 52 (FIG. 3).Preferably bushing 36 should be long enough to extend all the waythrough wall 12. Finally handle 24 (FIG. 2) is affixed to the free endof valve shaft 22.

As best seen in FIGS. 2 and 3, mounting assembly 10, through its bushing36, supports the entire valve 14 by its shaft 22. That is, there is norigid connection at all between mounting assembly 10 and valve housing16. Rather, when the operator rotates shaft 22 to either of itsoperative positions, bracket lip 42a engages screws 60a and 60b toprevent valve housing 16 from turning along with the shaft. Thus, rotorassembly turns relative to housing 16 to interconnect the proper tubes26. The engagement of lip 42a behind screw heads 64a and 64b alsoprevents shaft 22 from pulling out of bushing 36. However, some axialplay may be allowed in this engagement without adversely affectingoperation ofthe valve assembly.

On the other hand, if the operator inadvertently pushes sideways onshaft 22, this force is not transmitted to the internal plastic sealingmember on rotor assembly 20 because valve housing 16 is free to tilt orcock along with rotor assembly 20 i with respect to mounting assembly10. Thus, there is no relative movement between the rotor assembly andhousing 16 as would tend to permanently deform the sealing member andcause the valve to leak.

In some applications, it may also be desirable to protect rotor assembly20 from damage due to axial thrusts on valve shaft 22. This is easilyaccomplished by affixing a collar to shaft 22 just ahead of bushing 36after mounting the valve in assembly 10. Such a collar is indicated indotted lines at 70 in FIG. 2. Now any axial pushing forces on shaft 22are transmitted by collar 70 directly to bushing 36 and thence'tobracket 34. Accordingly, there is no appreciable relative movementbetween rotor assembly 20 and valve housing 16 which might tend todistort the sealing member within the valve.

My mounting assembly 10 is also able to support valve models having moretubes 26 and therefore requiring a different arrangement of itsbracket-engaging screws. One such valve model 14a is shown in FIG. 4. Itemploys a single screw in lieu of screws 60a and 60b on the FIG. 1valve. Screw 80 is similar to screw 60a or 60b except that it is locateddirectly below valve stem 22a and in position to engage in the V- shapedbracket groove 46 and, more specifically, in the rounded-out bottom 48thereof.

Screw 80 functions in much the same manner as screws 60a and 60b inFIGS. 1-3. That is, it prevents relative movement between valve housing16b and bracket 34 when the valve stem 22a is turned. On the other hand,the engagement between screw 80 and bracket 34 still permits the valve14a to cock as a unit with respect to the mounting assembly whensideways forces are applied inadvertently to its valve shaft 22a.Therefore no compression forces are developed which might cause coldflow of the plastic-sealing member.

It will be seen from the foregoing then that the described mountingassembly greatly prolongs the useful life of rotary fluid-switchingvalves. Not only may these valves now be used for longer periods withoutmaintenance, but also there is relatively little likelihood that thevalves will leak and spoil the results of any sampling procedure oranalysis being carried out. Still, the mounting assembly is relativelyeasy and inexpensive to make. Moreover, it may be installed quickly ondifferent valve models by relatively unskilled personnel.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

I claim:

1. An improved mounting assembly for a rotary valve of the type having ahousing and a rotor including a shaft protruding from the housing, saidmounting comprising:

A. a sleeve member for slidably receiving on and engaging said shaft;

B. means for securing said sleeve member to a support;

C. means projecting from said sleeve towards said housing 1. preventsaid housing from rotating with respect to said sleeve member when saidshaft is turned, and

2. allow said housing to cock with respect to said-sleeve member so thatthe entire valve moves as a unit when sideways forces are appliedt osaid shaft with the result that substantially no relative movementoccurs between said rotor and said housing due to said sideways forces.

2. An improved mounting assembly asdefined in claim 1 and furtherincluding means on saidmounting assembly for engaging portions of saidvalve to prevent said shaft from sliding axially out of said sleevemember.

3. An improved mounting assembly as defined in claim 2 and furtherincludingmeans for:

A. connecting to said shaft; and

B. slidably engaging said sleeve member to prevent said shaft frommoving axially relative to said sleeve member.

4. An improved mounting assembly for arotary valve of the type having ahousing and a rotor including a shaft protruding from the housing, saidmounting comprising:

A. a sleeve arranged to snugly engage over said shaft, said sleevehaving a collar at one end extending out away from its longitudinalaxis, said collar having a projecting portion arranged to I. preventsaid housing from rotating with respect to said mounting assembly whensaid shaft is turned, and

2. allow said housing to cock with respect to said sleeve so that theentire valve moves as a unit when sideways forces are applied to saidshaft whereby substantially no relative movement occurs-between saidrotor and said housing due to said sideways forces.

5. An improved mounting assembly as defined in claim 4 and furtherincluding means for retaining said shaft in said sleeve.

6. An improved mounting assembly for a rotary valve of the type having ahousing and a rotor including a shaft protruding from the housing, saidmounting comprising:

A. a generally T-shaped plate, the leg of said plate being folded backon itself to form an upstanding lip;

B. means defining an opening in said plate just above said lip, saidopening being appreciably larger than the cross section of said shaft;

C. a relatively long bushing for porting wall.

wherein;

A. said one bushing end has a reduceddiameter threaded portion adaptedto be received in said opening. and

B. said securing means is a nut adapted to be turneddown on saidthreaded portion and retain said bushing in said plate.

10. An improved mounting assembly as defined in claim 6:

A. wherein said bushing is engaged over said valve shaft with said lipfacing said housing, and

B. further including means projecting from said housing and engagingsaid lip so as l. to prevent said housing from rotating relative to saidplate when said shaft is turned, but

2. to allow said housing to cock relative to said plate when sidewaysforces are applied to :said shaft so that substantially no relativemovement occurs between said rotor and said housing due to said sidewaysforces.

1 1. An improved mounting assembly as defined in claim 10 wherein saidprojecting means overhangs said lip so as to prevent said housing frommoving axially away from said plate.

12. An improved mounting assembly as defined in claim 11 wherein saidprojecting means comprise one or more screws protruding from saidhousing toward said plate.

13. An improved mounting assembly as defined in claim 11 furtherincluding an abutment affixed to said shaft just in front of saidbushing to prevent axial movement of said shaft out of said bushing.

9. An improved mounting assembly as defined in claim 6

1. An improved mounting assembly for a rotary valve of the type having ahousing and a rotor including a shaft protruding from the housing, saidmounting comprising: A. a sleeve member for slidably receiving on andengaging said shaft; B. means for securing said sleeve member to asupport; C. means projecting from said sleeve towards said housing to 1.prevent said housing from rotating with respect to said sleeve memberwhen said shaft is turned, and
 2. allow said housing to cock withrespect to said sleeve member so that the entire valve moves as a unitwhen sideways forces are applied to said shaft with the result thatsubstantially no relative movement occurs between said rotor and saidhousing due to said sideways forces.
 2. allow said housing to cock withrespect to said sleeve member so that the entire valve moves as a unitwhen sideways forces are applied to said shaft with the result thatsubstantially no relative movement occurs between said rotor and saidhousing due to said sideways forces.
 2. An improved mounting assembly asdefined in claim 1 and further including means on said mounting assemblyfor engaging portions of said valve to prevent said shaft from slidingaxially out of said sleeve member.
 2. allow said housing to cock withrespect to said sleeve so that the entire valve moves as a unit whensideways forces are applied to said shaft whereby substantially norelative movement occurs between said rotor and said housing due to saidsideways forces.
 2. to allow said housing to cock relative to said platewhen sideways forces are applied to said shaft so that substantially norelative movement occurs between said rotor and said housing due to saidsideways forces.
 2. being secured on one end to said plate coaxiallywith said opening, D. means for securing said bushing to said plate. 3.An improved mounting assembly as defined in claim 2 and furtherincluding means for: A. connecting to said shaft; and B. slidablyengaging said sleeve member to prevent said shaft from moving axiallyrelative to said sleeve member.
 4. An improved mounting assembly for arotary valve of the type having a housing and a rotor including a shaftprotruding from the housing, said mounting comprising: A. a sleevearranged to snugly engage over said shaft, said sleeve having a collarat one end extending out away from its longitudinal axis, said collarhaving a projecting portion arranged to
 5. An improved mounting assemblyas defined in claim 4 and further including means for retaining saidshaft in said sleeve.
 6. An improved mounting assembly for a rotaryvalve of the type having a housing and a rotor including a shaftprotruding from the housing, said mounting comprising: A. a generallyT-shaped plate, the leg of said plate being folded back on itself toform an upstanding lip; B. means defining an opening in said plate justabove said lip, said opening being appreciably larger than the crosssection of said shaft; C. a relatively long bushing for
 7. An improvedmounting assembly as defined in claim 6 wherein said lip has arelatively large wedge-shaped slot positioned just below said opening.8. An improved mounting assembly as defined in claim 6 and furtherincluding means for securing said plate to a supporting wall.
 9. Animproved mounting assembly as defined in claim 6 wherein; A. said onebushing end has a reduced diameter threaded portion adapted to bereceived in said opening, and B. said securing means is a nut adapted tobe turned down on said threaded portion and retain said bushing in saidplate.
 10. An improved mounting assembly as defined in claim 6: A.wherein said bushing is engaged over said valve shaft with said lipfacing said housing, and B. further including means projecting from saidhousing and engaging said lip so as
 11. An improved mounting assembly asdefined in claim 10 wherein said projecting means overhangs said lip soas to prevent said housing from moving axially away from said plate. 12.An improved mounting assembly as defined in claim 11 wherein saidprojecting means comprise one or more screws protruding from saidhousing toward said plate.
 13. An improved mounting assembly as definedin claim 11 further including an abutment affixed to said shaft just infront of said bushing to prevent axial movement of said shaft out ofsaid bushing.